Portman Square
An iconic 1920s office building retrofit located within the Portman Estate Conservation Area.
- Type Retrofit
- Area 200,000 sq. ft
- Sector Workspace
- Service Cost Management
- Sustainability BREEAM Excellent, Target EPC A/B, Target WELL Rating, Net Zero Carbon Operations
Client(s) BGO
Architects Henning Larsen
Main Contractor TBC
Portman Square sits at the gateway between Oxford Street’s renowned shopping district and the prestigious residential neighbourhood of the Portman Estate in London’s West End.
CHP is providing full cost management services for this comprehensive commercial retrofit, introducing contemporary workspace standards while sensitively retaining key character features and embracing the building’s rich historical context.
- Cost management services — delivering full cost oversight from RIBA Stage 1 through to Stage 2
- Strategic procurement advisory — providing expert guidance to support informed decision-making throughout pre-construction
- Two-stage negotiated tender — currently procuring the project through a competitive two-stage process to achieve best value
- Due on site Q1 2026 — project on track to transition to construction phase on programme
Works include retention of the original façades, replacement of existing windows to improve thermal performance, and removal of the existing roof to create additional office floorspace, outdoor terraces and a biodiverse roof garden through biophilic design.
Designed to operate at net-zero carbon and fully electric, the development is targeting a 72% reduction in energy intensity, setting a new standard for sustainable commercial retrofit in London’s West End.
